Apparatus for drawing flat metal blanks into shells



April 15, 1947. H. H. GARY, JR 2,418,374

APPARATUS FOR DRAWING FLAT METAL BLANKS INTO SHELLS Filed June 13, 1944INVENTOR, HarZwelZfi. Gary, 72:,

ATTORNEY.

Patented Apr. 15. 1941 PATENT oFncr:

APPARATUS FOR BLANK DRAWING FLAT METAL S INTO SHELLS Hartwell H. Gary,(in, Norfolk, Va.

Application June 13, 1944, Serial No. 540,110

- 1 Claim. 1

My invention relates to the plastic deformation of metals and moreparticularly to the deep drawing of fiat metal blanks into shells orcups, and it has for its object the development of a new and improvedapparatus for producing deep drawn shells in fewer operations than hasbeen possible under methods hitherto in use.

In order that there may be no misunderstanding as to the nomenclatureused in the specification and in the subsequent claims, I shall refer tothe work piece as it is received into the press, and whether or not itis flat or has been previously deformed, as the blank"; to that part ofthe work piece which has not entered the die as the flange; to that partof the work piece which has entered the die as the shell; and to thework piece as a whole, including the flange and the shell, as the work"or the "work Piece."

My new and improved apparatus provides a means of drawing in oneoperation and with one set of dies, a shell which is very deep ascompared to its diameter.

Generally my apparatus involves the preliminary cooling of the center ofthe hot blank as the punch descends and forces the metal through the dieand to continue cooling the metal adjacent the punch as it passes intoand through the die.

It is well known that the resistance to deformation of metals,particularly ferrous metals,

varies according to their temperature. and that this resistance, both intension and in compression of such metals, becomes less as thetemperature increases above ordinary atmospheric temperature. It is thepurpose of my invention to utilize this phenomenon to the end that theflange or perimeter portion of the work may be hot, making it easier toovercome the compressive resistance of the metal in thi portion and thatthe shell portion may be cooler and therefore possess greater tensilestrength and be more able to resist the tensile strains which are set upin this portion.

Other objects will in part be obvious and in part be pointed outhereinafter.

To the attainment of the aforesaid objects and ends the invention stillfurther resides in those novel method features and apparatus details ofconstruction and operation, all of which will first be fully describedin the following detailed description and then be specifically pointedout in the accompanying drawings in which:

Fig. 1 is a central vertical section and Part elevation of a hydraulicpress adapted to carry out 5 my invention.

Fig. 2 is a plan view of the same. 1

Figs. 3 and 4 are schematic detail vertical sections showingrespectively a shell about to be formed (Fig. 3) and a completed shell(Fig. 4).

In the drawings in which like numerals of reference indicate like partsin all the figures, i represents the bolster or stationary platen of ahydraulic punch press, 2 the movable platen, 3 the standards on whichthe movable platen slides up and down, 4 the passage through thestationary platen and 5 the punch. The die through which the metal ofthe heated blank 8 is drawn is indicated by the numeral 6 while Idesignates the blank holder, and ii represents the blank holder platen,I! the cylinders, l3 the pistons and it the piston rods for operatingthe blank holder.

The movable platen 2 with its punch is operated by hydraulic fluid.admitted and controlled in the usual way, via a port l5 in the cylinderi6, and acting on the piston ii that carries the platen 2. The blankholder cylinders I! with their platen and blank holder may be operatedby compressed air or otherwise, or springs may 80 be substituted inplace of cylinders for exerting I pressure on the blank holder. As thedetails of the punch press per se are well known further descriptionthereof is unnecessary. While the drawings of my apparatus show a "downmov- 3 ing" press; that is, one with the cylinder at the top and itsworking stroke taking place in a downward direction, it is perfectlyobvious that an up moving" press or even a horizontal or inclined pressmay be used.

In the embodiment illustrated the cooling of the metal takes place onits top face by means of .a coolant admitted into the space l8 througha. pipe '9 and withdrawn through a pipe I0 by a 45 suction pump (notshown).

From the foregoing description taken in connection with the accompanyingdrawings it is thought the construction of the apparatus. and themethods. employed will be clear to those 50 skilledinthe art.

What 1 claim ia: In apparatus-tor forming elongated shell: a stationarylaten having a passage; a movable platen; a punch carried by themovableplaten;

means for lowering and raising the movable 5 platen toward and from thestationary platen; a die on the stationary platen to receive a flat hotblank thereon; a blank holder over the die and having a passage for thepunch; said blank holder having a central opening constituting a chamberwhose bottom is constituted by the blank and through which the punchpasses: and means for admitting acoolant to and withdrawing the samefrom said chamber for purposes described.

HARTWEIL H. GARY, Ja.

REFERENCES CITED The following references are of record in the file ofthis patent:

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